Transient Damage Strategy (T D S) is a process that functions to effectively and economically alleviate critical safety, ecological, and commercial deficiencies presently existing within the waterborn transportation industry.
TDS is a process that addresses the problems of loss of ships tank contents into waters, and intrusion of water into ships tanks, and provides, as near as is practicable, viable, and reliable solutions therefore.
It is recognized that ship's liquid loaded tanks must be provided with unrestricted vents to preclude over pressurization that would otherwise result from expansion and contraction of tank contents, and to allow for filling and emptying of tanks, and it is recognized that, subsequent to underwater penetration of tanks, free communication of ambient air or other influencing medium, through tank vents or other tank penetrations allows rapid flooding of empty tanks, and/or loss of that portion of tank contents above the water level, thereby contributing to pollution and degradation of ship's stability and buoyancy.
Commercial vessels employed in the transportation of petroleum products are particularly susceptible to rapid loss of large quantities of cargo due to the requirement to maintain ullage areas of tanks inerted to an over pressure of approximately 1.5 psi above atmospheric pressure, whereby, upon penetration of the tank below the outside water level, outboard flow of tank contents is compelled to occur at a faster rate and to a greater extent.
Control of and/or recovery from extensive under water hull damage by implementation of classic damage control procedures, as employed on most war ships, is not realistic in the area of merchant shipping where economics require near total automation of ship operation and proportional reduction of manning levels. Further, it has been demonstrated that distant located personnel and equipments, which are dedicated to assisting merchant vessels in containment and recovery of spilled petroleum products, are not to be relied upon to respond during the most critical early stages of casualty.
With the foregoing in mind, it follows that any practical system for preventing gross contamination of waters and shorelines, and for protection of ship stability and buoyancy, must be installed in the ship, and must be active at the moment of incident to be effective. To be viable, under merchant shipping conditions, the system must be safe, economical, reliable, easily operable, and must not require continuing maintenance, reliance on operation of ship's systems, or continuing detraction of personnel from other duties.
As it was determined that no single system or piece of equipment could meet requirements of preceding paragraph, TDS was developed by considering each element of the overall problem with ends to elemental solution and to ultimate combining of all elements of the solution into a cohesive and comprehensive process which, in addition to considering solution of problems, considers that the system must be versatile enough to be effective when, due to unforeseen circumstances, predetermined solutions are not totally valid.